In a wireless communications system, a base station performs uplink channel estimation and demodulation by using an uplink (UL for short) demodulation reference signal (DMRS for short) sent by user equipment (UE for short), and the UL DMRS may also be used to assist in uplink timing, signal-to-noise ratio estimation, channel measurement, and the like. The UE sends a physical uplink shared channel (PUSCH for short) and the UL DMRS to the base station, where the PUSCH is used to carry uplink data. The UE may further send uplink control information (UCI for short), where the UCI includes a channel quality indicator (CQI for short)/a precoding matrix indicator (PMI for short), a rank indication (RI for short), and an acknowledgement (ACK for short) or a negative acknowledgement (NACK for short).
At present, a small cell-related technology appears in the prior art. Because coverage of a small cell is relatively small, and a moving speed of UE is slow, there is a relatively good correlation between channel quality and a channel time-frequency domain of the UE in the small cell. Therefore, the UE usually sends a UL DMRS only over the 4th symbol, that is, symbol 3, of an uplink subframe sent to a base station in the small cell, sends at least one of an ACK and a NACK over the 3rd, 5th, 10th, and 12th symbols, that is, symbols 2, 4, 9 , and 11 , sends an RI over the 2nd, 6th, 8th, and 11th symbols, that is, symbols 1, 5, 7, and 10, and sends data over the 11th symbol, that is, symbol 10, over which the UL DMRS is originally sent in the uplink subframe, so that more resources are used to send the data, thereby improving resource utilization and spectral efficiency.
However, in the prior art, performance of demodulating for at least one of the ACK or the NACK and the RI in the uplink subframe by the base station in the small cell may be degraded, thereby reducing a data transmission rate and a network throughput.